Sometimes a passive crossover is just stupid...

[mhardy6647]

There is a battery-powered preamp here. Probably makes rather more sense than a power amplifier, though, I'll give you that.
Said preamp is, in fact, not actually constructed. It is, in fact a box of parts -- but an afternoon's work, and it could become a preamp.

Quickie 1.1 Battery Powered Directly Heated Tube Preamplifier Kit – Bottlehead Archives

As an aside -- I have, on long, sunny summer days, sometimes mused about using DC straight off of our rooftop photovoltaic arrays to power a vacuum tube amplifier.

 

[gberchin]

I have, on long, sunny summer days, sometimes mused about using DC straight off of our rooftop photovoltaic arrays to power a vacuum tube amplifier.

https://audiophilestyle.com/ca/bits...ality-of-panels-batteries-and-the-grid-r1072/

 

[kyuu]

https://audiophilestyle.com/ca/bits-and-bytes/the-audio-impact-of -solar-panels-and-battery-backup-comparing-sound-quality-of-panels-batteries-and-the-grid-r1072/

This guy's "testing" was about as useless as it gets. The fact that he's using $2000 XLR cables is pretty indicative that he's a typical "golden ear" audiophile. Pretty amusing that his setup full of extraordinarily expensive gear (including a "power conditioner", for chrissakes) and interconnects apparently completely fails to insulate his system from the influences of the incoming electricity.

 

[mhardy6647]

I must say I've given no thought whatsoever as to the audiophile impact of our PVs.
Maybe my hifi simply isn't resolving enough.

 

[Randyman...]

A bit OT: RME's new lab-grade PSU actually gets their DAC (not sure which ADI model it was) to measure a lower noise floor than when using batteries. These kinds of SINAD-only improvements are not something I chase personally, but was impressed to see that the AC PSU could "best" the same DAC driven by batteries (even if the difference is not audible to anyone but an AP test set with no ears)... That is all...